Method and system for intelligent networking trigger contention resolution in IP multimedia subsystem networks

ABSTRACT

A method of receiving a first InitialIN message, determining if the first InitialIN message is a mobile origination, determining if an mscAddress comprising the first InitialIN message is an IP Multimedia Subsystem (IMS) MSC address, and establishing DMS IN services with an SCF/SCP and performing VCC anchoring for a DMS communication session with a VCC SCF/SCP if the InitialIN is a mobile origination and if the mscAddress is an IMS MSC address.

TECHNICAL FIELD

The present invention is directed to a method and system for triggercontention resolution with IP multimedia subsystem networks.

BACKGROUND

In recent years subscribers have been using cell phones in moretechnologically diverse environments. Subscribers use mobile phones incircuit switched environments, packet switched environments, Wi-Fienvironments as well as other environments. Dual mode service (DMS),that is, use of a phone in a Wi-Fi environment as well as other cellularenvironments, has become more popular. Wi-Fi access points are plentifulin industry (e.g., coffee shops, airports, hotels) as well as at home.With the advent of Internet Protocol (IP) Multimedia Subsystem (IMS)networks, dual mode subscribers may use their mobile phones in bothWi-Fi and cellular networks. DMS calls across IMS networks and cellularnetworks have to be anchored in an IMS network. This anchoring requiresadding a new service control point (SCP) or service control function(SCF) element to the IMS network (as per VCC). The additional SCF/SCPused to support DMS, however, is not integrated on the same platform asexisting Intelligent Networking (IN) services. Offering IN servicesacross separate SCF/SCPs may lead to trigger contention.

A need exists, therefore, for a way to address trigger contention issuesthat arise when a DMS subscriber wants to access their existing INservices across cellular and IMS networks.

SUMMARY

A method in one application of receiving a first intelligent networking(InitialIN) message, determining if the first InitialIN message is amobile origination, determining if an mscAddress comprising the firstInitialIN message is an IP Multimedia Subsystem (IMS) mobile switchingcenter (MSC) address (mscAddress), and establishing DMS IN services withan SCF/SCP and performing VCC anchoring for a DMS communication sessionwith a VCC SCF/SCP if the InitialIN is a mobile origination and if themscAddress is an IMS MSC address.

A system in another application comprising a service switching functionSSF)/service switching point (SSP), an SCF/SCP, a VCC SCF/SCP, a DMS INService Provider wherein the DMS IN Service Provider is communicativelycoupled to the SSF/SSP, SCF/SCP and VCC SCF/SCP. Furthermore, the DMS INService Provider is configured to establish IN services for a dual modecall via the SSF/SSP and SCF/SCP, and the DMS IN Service Provider isconfigured to perform VCC anchoring in an IMS network via the VCCSCF/SCP.

DESCRIPTION OF THE DRAWINGS

Features of example implementations of the invention will becomeapparent from the description, the claims and the accompanying drawingsin which:

FIG. 1 is a system diagram used to provide a simple illustration ofvoice call continuity (VCC) anchoring.

FIG. 2 is a system diagram of a network in which the system forintelligent networking trigger contention resolution in IP multimediasubsystem networks may reside.

FIG. 3 is a sample call flow of messages that may be sent in support ofthe system and method.

FIG. 4 is a representation of one implementation of a method forintelligent networking trigger contention resolution in IP multimediasubsystem networks.

DETAILED DESCRIPTION

The IMS network defines an architecture meant to provide a means forcarriers to create an open, standards-based network that deliversintegrated multimedia services to subscribers. An IMS subscriber may bea dual mode subscriber (DMS), that is, a subscriber that may access theIMS network via a cellular interface or a Wi-Fi interface. Dual modesubscribers may desire their existing IN services regardless of whetherthey are located in a cellular network or a Wi-Fi network.

Calls or communication sessions from a dual mode subscriber must beanchored in an IMS network. A call or communication session may be acircuit switched call, a data call, a packet call, or any other means ofestablishing communication between two mobile devices or a mobile deviceand a landline device. Anchoring a call in an IMS network requires thatcall processing involve a VCC SCF/SCP. Because there can only be oneSCF/SCP address per trigger, trigger contention arises. The triggeredSCF/SCP address is the VCC SCF/SCP address. Thus a dual modesubscriber's IN services must be negotiated with the VCC SCF/SCPregardless if the subscriber's services reside on another SCF/SCP.

Turning to FIG. 1, which is a simplified network diagram 100 that may beused for the purpose of illustrating VCC anchoring. In looking atcomponents of the network 100, an IMS switch 105 may reside in an IMSnetwork 107. The IMS network 107 may be in communication with a Wi-Finetwork 109. The cellular network 110 may be a GSM network, an analognetwork, a CDMA network or any other type of circuit or packet switchedcellular network. The service switching function (SSF)/service switchingpoint (SSP) 120 may be a node in the network 100 that provides callprocessing functionality as well as access to a service control point(SCP). The VCC SCF/SCP 115 operates as an SCP in the network 100. An SCPmay contain service logic and data that informs an SSF/SSP how to treata call.

As mentioned, dual mode subscribers who have IMS service may need tohave their calls anchored in the IMS network 107. If the IMS subscriberis not in the IMS network 107, for example, the subscriber may be in aGSM or other cellular network 110, when the IMS subscriber originates acall, the call must be anchored in the IMS network 107. In the processof anchoring a call, the SSF/SSP 120 may send an InitialIN message (forexample, a CAMEL Application Part InitialDP message) to the VCC SCF/SCP115. The VCC SCF/SCP 115 may send a temporary number routing number backto the SSF/SSP 120. The SSF/SSP 120 may use the temporary routing numberto route the call into the IMS network 105. In this context, the essenceof VCC anchoring comprises the VCC SCF/SCP 115 providing the SSF/SSP 120a temporary routing number and routing the call to an IMS network usingthe temporary routing number.

Turing now to FIG. 2, a system 200 diagram of an example network inwhich the system for intelligent networking trigger contentionresolution in IP multimedia subsystem networks may reside. The system200 may provide a dual mode subscriber with IN services regardless ofwhether the subscriber is operating in a cellular network or a Wi-Finetwork.

A dual mode subscriber may access the IMS network form a cellularnetwork 205. The cellular network 205 may be communicatively coupled toa service switching function (SSF) or service switching point (SSP) 210.The SSF/SSP 210 may be communicatively coupled with a DMS IN ServiceProvider 222 that resides on a service broker 220. The DMS IN ServiceProvider 222 may communicate with other nodes in the network 200 via theservice broker 220. The application protocol linking the SSF/SSP 210 andthe DMS IN Service Provider 222 may be a Customized Applications forMobile network Enhanced Logic (CAMEL) application part (CAP), anAdvanced Intelligent Networking (AIN) protocol, a wireless intelligentnetworks (WIN) protocol, or an Intelligent Networking Application Part(INAP) protocol. Typically the SSF/SSP 210 queries a service controlpoint (SCP). An SCP may contain service logic and data that informs anSSF/SSP 210 how to treat a call. In the system 200, however, the SSF/SSP210 may communicate with a DMS IN Service Provider 222 instead of an SCPto get service logic and data that may inform the SSF/SSP 210 how totreat a call.

The DMS IN Service Provider 222 may be communicatively coupled to anSCF/SCP 225. The SCF/SCP 225, among other responsibilities, may manageservice control. The SCF/SCP 225 may communicate with the DMS IN ServiceProvider 222 using a CAP, AIN, WIN, or INAP communication protocol. TheDMS IN Service Provider 222 may also be communicatively coupled to anIM_SSF/SSP 240 and a VCC SCF/SCP 245 that may reside on an IMS switch235. The IMS switch 235 may reside in an IMS network. The VCC SCF/SCP245 may communicate with the DMS IN Service Provider 222 using a CAP,AIN, WIN, or INAP communication protocol. The IMS switch 235 may also becommunicatively coupled to a Wi-Fi network 250. A DMS subscriber mayoriginate or terminate calls from the Wi-Fi network 250.

The SSF/SSP 210, service broker 220, DMS IN Service Provider 222, andSCF/SCP 225 components are shown as separate entities. The components210, 220, 222, 225, however, may reside on a single network node, or thecomponents 210, 220, 222, 225 may reside in separate network nodes, orthe components 210, 220, 222, 225 may reside in any combination in thesame or different network nodes.

Although the DMS IN Service Provider 222 is depicted in the ServiceBroker 220, the DMS IN Service Provider 222 may reside in other nodes ina network. Furthermore, functionality ascribed to the DMS IN ServiceProvider 222 may be performed by another node in a network, or the DMSIN Service Provider 222 functionality may be distributed throughout anetwork.

The system 200 in one example comprises a plurality of components suchas one or more of computer software components. A number of suchcomponents can be combined or divided in the system 200. An examplecomponent of the system 200 employs and/or comprises a set and/or seriesof computer instructions written in or implemented with any or a numberof programming languages, as will be appreciated by those skilled in theart. The system 200 in one example comprises a vertical orientation,with the description and figures herein illustrating one exampleorientation of the system 200, for explanatory purposes.

The system 200 in one example employs one or more computer-readablesignal-bearing media. The computer-readable signal-bearing media storesoftware, firmware and/or assembly language for performing one or moreportions of one or more implementations of the invention. Thecomputer-readable signal-bearing medium for the system 200 in oneexample comprise one or more of a magnetic, electrical, optical,biological, and atomic data storage medium. For example, thecomputer-readable signal-bearing medium comprise floppy disks, magnetictapes, CD-ROMs, DVD-ROMs, hard disk drives, and electronic memory.

Turning to FIG. 3, which depicts a sample call flow 300 that may beassociated with establishing services for a DMS subscriber when the DMSsubscriber originates a call in a cellular network. When a DMSsubscriber originates a call/communication session in a cellular networkthe call may come into an SSF/SSP such as the SSF/SSP 210 of FIG. 2. Aspart of registration, Homer Location Register (HLR) data may be storedin a Visitor Location Register (VLR). The HLR data stored in the VLR mayinclude the address of an SCP that provides service control for thecall. The SSF/SSP 210 may query the VLR to determine the SCP addressthat provides service control for the call. In this example, the HLR maybe configured such that the DMS IN Service Provider 222 is the entitythat is supposed to provide IN services to support the call.

The SSF/SSP 210 may begin establishing services for the incoming call bysending a first InitialIN message 305 to the DMS IN Service Provider222. If the protocol supported by the system 200 is CAP or INAP then thefirst InitialIN message 305 may be an InitialDP. For an AIN protocol thefirst InitialIN 305 message may be an Info_Analyzed, Info_Collected orTermination_Attempt message. In the case of a WIN protocol the firstInitialIN message 305 may be an OriginationRequest.Invoke orAnalyzedlnfo.Invoke. Regardless of the protocol used, an InitialINmessage may comprise at least an mscAddress and an eventTypeBCSM or someequivalent to each of these two fields. The mscAddress is the addressassigned the GMSC/MSC. For mobile originations, the mscAddress carriesthe international E.164address of the serving VMSC. For mobileterminations, the mscAddress carries the international E.164 address ofthe GMSC. For mobile terminations in a VMSC (VT calls), the mscAddresscarries the international E.164 address of the serving VMSC. The eventtype that is a basic call state model (eventTypeBCSM) may indicate thearmed BCSM DP event resulting in the InitialIN message operation.

The DMS IN Service Provider 222 may be configured with a table of MSCadresses that are addresses of MSCs that comprise an IMS network. TheDMS IN Service Provider 222 may compare the mscAddress received in thefirst InitialIN mesage 205 with the table of IMS MSC addresses todetermine if the mscAddress may be an address of an MSC that resides inthe IMS network. If the mscAddress is an IMS MSC and the eventTypeBCSMindicates that this is a mobile origination, the DMS IN Service Provider222 may store the contents of the first InitialIN message 305 receivedfrom the SSF/SSP 210 and send a second InitialIN message 310 to theSCF/SCP 225. As described above, depending on the IN protocol (AIN,INAP, WIN, CAP) used in the system 200, the second InitialIN message maybe an InitialDP, Info_Analyzed, Info_Collected orOriginationRequest.Invoke. The DMS IN Service Provider 222 may use thefirst InitialIN message 305 received to populate the second InitialINmessage 310, or the DMS IN Service Provider 222 may forward the firstInitialIN message 305 to the SCF/SCP 225. Regardless, the service brokermay store the contents of the first InitalINMsg 305 for later reference.Based on the data received in the first InitialIN messsage, the DMS INService Provider 222 may query a home subscriber server (HSS) or anydatabase used by the system to store data based on a service key todetermine which SCF/SCP 225 to send the second InitialIN message 310.

The SCF/SCP 225 may engage in service logic processing. Depending on theservice invoked, different event detection points may be set. TheSCF/SCP 225 may send a first INConnect message 315 to the DMS IN ServiceProvider 222. The first INConnect message 315 may be a CAP Connect, anINAP Connect, a WIN OriginationRequestReturnResult, a WINAnalyzedInformationReturnResult, an AIN Analyze_Route, or an AINForward_Call message. The first INConnect message 315 may contain a newb-party number or connected number, that is a new destination phonenumber. The DMS IN Service Provider 222 may store the b-party number forlater reference. The DMS IN Service Provider 222 may construct a thirdInitialIN message 320. The third InitialIN message 320 may beconstructed with the parameters received in the first InitialIN message305 and previously stored by the DMS IN Service Provider 222. The onefield that may differ from the first InitialIN message 305 is theb-party number of the third InitialIN message 320. The third InitialINmessage 320 may contain the connected number passed to the DMS INService Provider 222 in the first INConnect message 315. If the firstINConnect message 315 that did not contain a connected number, such as aContinue message in the case of CAP, the third InitialIN message 320 maycontain the b-party number received in the first InitialIN message 305and previously stored by the DMS IN Service Provider 222. The thirdInitialIN message 320 is sent to the VCC SCF/SSP 245.

The VCC SCF/SCP 245 may respond to the third InitialIN message 320 witha second INConnect message 325. The second INConnect message 325 maycontain a temporary routing number, such as, for example, a IMS RoutingNumber (IMRN). Thus the VCC SCF/SCP 245 is in the process of anchoringthe call in IMS. The DMS IN Service Provider 222 may construct a thirdINConnect Message 330 using the parameters received in the firstINConnect message 315 from the SCF/SCP 225. The IMRN received from theVCC SCF/SCP 24, however, may be passed back in the third INConnectmessage 330 in lieu of any connected number received in the firstINConnect message 315. The SSF/SSP 210 may use the IMRN to route thecall to the IMS network.

The SSF/SSP 210 may send event detection point (EDP) related messagingto the DMS IN Service Provider 222. The DMS IN Service Provider 222 mayforward these messages to the SCF/SCP 225 as if the SSF/SSP 210 iscommunicating directly with the SCF/SSP 225. The SSF/SSP 210 and theSCF/SCP 225 may continue further communication with each other via theDMS IN Service Provider 222 in this manner. These communications mayalso include communications related to handovers. In these furthercommunications, the DMS IN Service Provider 222 may pass throughmessages between the SSF/SSP 210 and the SCF/SCP 225 without performingany operations on the messages beyond routing the messages.

In the example call flow above, the mscAddress received in the firstInitialIN message was not an IMS MSC address and the eventTypeBCSMreceived in the first InitialIN message indicated that the call was amobile origination. If, however, the MSC address is an IMS MSC address,regardless of whether the eventTypeBCSM indicates that this is a mobileorigination or mobile termination, VCC anchoring is not applicable. TheDMS IN Service Provider 222 simply passes IN messages through to theintended recipient.

If the mscAddress received in the first InitialIN message is not an IMSaddress and the eventTypeBCSM received in the first InitialIN messageindicates that the call is a mobile termination, only VCC anchoring isinvoked. No other IN services are invoked. In this case, any other INmessages are passed through the DMS IN Service Provider 222 to themessage destination. In all cases above, any messaging related tohandovers may be handled in the same manner as any other call in thisstate.

Turning now to FIG. 4, which is an illustration of a method 400 forintelligent networking trigger contention resolution in IP multimediasubsystem networks. The method 400 in this example may reside in the DMSIN Service Provider 222 resident on the Service Broker 220. The method400 in other implementations, however, may reside in other nodes in anetwork.

The method 400 begins in a start state 405 ready to receive IN messages410. The method 400 determines if an incoming IN message is an InitialINmessage 415. As previously described, depending on the network protocolsupported, the InitialIN message may be one of many different types. Forexample, if the method 400 reside in a CAP or INAP network the initialIN message may be an InitialDP. In an AIN protocol network the InitialINmessage may be an Info_Analyzed or Info_Collected message. In the caseof a WIN protocol network the InitialIN message may be anOriginationRequest.Invoke. As before, each of these messages maycomprise at least an mscAddress and an eventTypeBCSM or some equivalentof these two fields. If the message is not an InitialIN message, themethod 400 continues waiting for IN messages 410.

If the incoming message is an InitialIN message, the method 400determines if the mscAddress is in the table of MSC addresses that areIMS MSC addresses 420. If the mscAddress is in the table 425, the method400 performs IMS MSC handling 430. When the method 400 is performing IMSMSC handling 430, the method 400 simply passes messages between sendersand receivers while a call is established. VCC anchoring is notapplicable, and thus not performed. Once the call completes, the method400 continues waiting for IN messages 410.

If the mscAddress is not in the table of MSC addresses that are IMS MSCaddresses 425, the method 400 determines the eventTypeBCSM 435 passed inthe InitialIN message. If the eventTypeBCSM indicates that the call isnot a mobile termination 440 (eventTypeBCSM is not DP12), the method 400checks to see if the call is a mobile origination 445. If theeventTypeBCSM indicates the call is not a mobile origination 445 (theeventTypeBCSM is not DP2), the method 400 continues waiting for INmessages 410.

If the eventTypeBCSM indicates that the call is a mobile termination440, the method 400 enters termination handling 450. In terminationhandling the DMS IN Service Provider 222 performs VCC anchoring, but theDMS IN Service Provider 222 does not perform any other IN services.Instead, IN services may be performed from the IMS network afteranchoring. The method 400 may then continue waiting for IN messages 410.

If the eventTypeBCSM indicates the call is a mobile origination 445, themethod 400 may proceed to origination handling 445. In originationhandling 445 the method 400 may handle messages as shown for the DMS INService Provider 222 in FIG. 3. The method 400, therefore, may handle anInitialIN message from the SSF/SSP 210 and send an InitialIN message tothe SCF/SCP 220. Message handling may proceed as described in FIG. 3.The method 400 may then continue to wait for IN messages 410.

The steps or operations described herein are just for example. There maybe many variations to these steps or operations without departing fromthe spirit of the system and method. For instance, the steps may beperformed in a differing order, or steps may be added, deleted, ormodified.

Although example implementations of the system and method have beendepicted and described in detail herein, it will be apparent to thoseskilled in the relevant art that various modifications, additions,substitutions, and the like can be made without departing from thespirit of the method and these are therefore considered to be within thescope of the system and method as defined in the following claims.

1. A method comprising the steps of: receiving a first intelligentnetworking (InitialIN) message; determining if the first InitialINmessage is a mobile origination; determining if a mobile switchingcenter (MSC) address (mscAddress) comprising the first InitialIN messageis an IP Multimedia Subsystem (IMS) MSC address; and establishing dualmode service (DMS) intelligent networking (IN) services with a servicecontrol function (SCF)/service control point (SCP) and performing VCCanchoring for a DMS communication session with a voice call continuity(VCC) SCF/SCP if the InitialIN is a mobile origination and if themscAddress is not an IMS MSC address.
 2. The method of claim 1 whereinthe step of receiving an InitialIN message further comprises performingat least one of a: CAMEL signaling protocol; Advanced IntelligentNetworking signaling protocol; Wireless Intelligent Networking signalingprotocol; and Intelligent Networking Application Protocol.
 3. The methodof claim 1 wherein the InitialIN message contains the mscAddress and anevent type that is a basic call state model (eventTypeBCSM).
 4. Themethod of claim 1 wherein the InitialIN message is at least one of a:CAMEL Application Part InitialDP message; Advanced IntelligentNetworking Info_Analyzed message; Advanced Intelligent NetworkingInfo_Collected message; Advanced Intelligent NetworkingTermination_Attempt message; Wireless Intelligent NetworkingOrigination.Request.Invoke message; Wireless Intelligent NetworkingAnalyzedInfo.Invoke; and Intelligent Networking Application PartInitialDP message.
 5. The method of claim 1 wherein determining if theInitialIN message is a mobile origination further comprises determininga type of event that is a basic call state model (eventTypeBCSM).
 6. Themethod of claim 1 wherein determining if an mscAddress is an IMS MSCaddress further comprises storing a table of IMS MSC addresses.
 7. Themethod of claim 6 wherein an mscAddress received in the InitialINmessage is compared with the table of IMS MSC addresses.
 8. The methodof claim 1 wherein establishing IN services and performing VCC anchoringfurther comprises performing VCC anchoring after establishing INservices.
 9. The method of claim 1 wherein establishing IN services withan SCF/SCP further comprises: storing parameters received in the firstInitialIn message; and sending a second InitialIN message to the SCF/SCPif the mscAddress is not in the table of IMS MSC addresses and theeventTypeBCSM indicates a mobile origination wherein the secondInitialIN message is comprised of the parameters of the first IntialINmessage.
 10. The method of claim 1 wherein performing VCC anchoringfurther comprises: sending an InitialIN message to the VCC SCF/SCP;receiving an INConnect message from the VCC SCF/SCP; storing a temporaryrouting number received from the VCC SCF/SCP; and sending the temporaryrouting number to the service switching function (SSF)/service switchingpoint (SSP) in an InitialIN message.
 11. The method of claim 1 whereinif the mscAddress in not an IMS MSC address, VCC anchoring is performedand IN services are not established via the SCF/SCP.
 12. A systemcomprising: computer-readable non-transitory media; a service switchingfunction (SSF)/service switching point (SSP); a service control function(SCF)/service control point (SCP); a voice call continuity (VCC)SCF/SCP; a dual mode service (DMS) intelligent networking (IN) ServiceProvider wherein the DMS IN Service Provider is communicatively coupledto the SSF/SSP, SCF/SCP and VCC SCF/SCP; the DMS IN Service Providerconfigured to establish IN services for a dual mode communicationsession via the SSF/SSP and SCF/SCP; and the DMS IN Service Provider isconfigured to perform VCC anchoring in an IP Multimedia Subsystem (IMS)network via the VCC SCF/SCP.
 13. The system of claim 12 wherein the DMSIN Service Provider is communicatively coupled to the SSF/SSP, SCF/SCPand VCC SCF/SCP with at least one of a/an: CAMEL signaling protocol;Advanced Intelligent Networking signaling protocol; Wireless IntelligentNetworking signaling protocol; and Intelligent Networking ApplicationProtocol.
 14. The system of claim 12 wherein the DMS IN Service Providerconfigured to establish IN services further comprises a DMS IN ServiceProvider configured to receive an InitialIN message wherein theInitialIN message is at least one of a: CAMEL Application Part IntialDPmessage; Advanced Intelligent Networking Info_Analyzed message; AdvancedIntelligent Networking Info_Collected message; Advanced IntelligentNetworking Termination_Attempt message; Wireless Intelligent NetworkingOrigination Request Invoke message; and Intelligent NetworkingApplication Part InitialDP message.
 15. The system of claim 12 whereinthe DMS IN Service Provider is configured to maintain a table of MSCaddresses comprising MSCs resident in an IMS network.
 16. The system ofclaim 12 wherein establishing IN services for a dual mode communicationsession further comprises: receiving a first InitialIN message from theSSF/SSP and storing the parameters of the first InitialIN message;comparing an mscAddress received in the first InitialIN message to thetable of IMS MSC addresses; determining an event type that is a basiccall state model (eventTypeBCSM) received in the first InitialINmessage; and establishing DMS IN services via the SCF/SCP and anchoringthe DMS communication session in IMS, if the eventTypeBCSM indicates thecommunication session is a mobile origination and the mscAddress is theaddress of an MSC not in the table of IMS MSC addresses.
 17. The systemof claim 16 wherein establishing DMS IN services further comprises:sending a second InitialIN message to the SCF/SCP comprised of theparameters of the first IntialIN message; receiving a first INConnectmessage from the SCF/SCP; storing a connected number received in thefirst INConnect message; and storing the parameters of the firstINConnect message.
 18. The system of claim 17 wherein anchoring the DMScommunication session in IMS further comprises: sending a thirdInitialIn message to the VCC SCF/SCP wherein the connected number issent in the third InitialIN message; receiving a second INConnectmessage from the VCC SCF/SCP; storing a temporary routing numberreceived from the VCC SCF/SCP; and sending a third INConnect message tothe SSF/SSP wherein the third INConnect message is comprised of theparameters stored from the first INConnect message and if a temporaryrouting number is stored, putting the temporary routing number in thethird INConnect message.
 19. The system of claim 16 wherein the DMS INservices are established before the communication session is anchored inIMS.
 20. The system of claim 16 wherein VCC anchoring is not performedif the mscAddress is in the table of IMS MSC addresses.
 21. The systemof claim 16 wherein if the mscAddress is not in the table of IMS MSCaddresses and the eventTypeBCSM indicates a mobile termination VCCanchoring is performed and IN services are not established via theSCF/SCP.